Fecal Microbiota, Live-jslm for the Prevention of Recurrent Clostridioides difficile Infection : Subgroup Analysis of PUNCH CD2 and PUNCH CD3

GOALS

To assess fecal microbiota, live-jslm (REBYOTA, abbreviated as RBL, formerly RBX2660) efficacy and safety in participants grouped by recurrent Clostridioides difficile infection (rCDI) risk factors and treatment-related variables.

BACKGROUND

RBL is the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration for the prevention of rCDI in adults after antibiotic treatment for rCDI.

STUDY

Treatment success rates across subgroups for PUNCH CD3 (NCT03244644) were estimated using a Bayesian hierarchical model, borrowing data from PUNCH CD2 (NCT02299570). Treatment-emergent adverse events were summarized for the double-blind treatment period within 8 weeks.

RESULTS

Treatment differences between RBL and placebo at 8 weeks were similar to the total population for most subgroups. Treatment effect sizes were similar between CDI tests, higher for oral vancomycin courses >14 days versus ≤14 days and higher for antibiotic washout periods of 3 days versus ≤2 days. The largest reductions in the rate of rCDI with RBL versus placebo were observed for participants with a 3-day CDI antibiotic washout period and participants with ≥4 previous CDI episodes. Most RBL-treated participants experienced TEAEs that were mild or moderate in severity and related to preexisting conditions.

CONCLUSION

This analysis provides further evidence of RBL efficacy and safety across subgroups, including those at high risk for rCDI.

Safety of fecal microbiota, live-jslm (REBYOTA™) in individuals with recurrent Clostridioides difficile infection: data from five prospective clinical trials

Background

Microbiota-based treatments reduce the incidence of recurrent Clostridioides difficile infections (rCDIs), but prospectively collected safety data needed to broaden patient access and protect public health have been limited.

Objectives

We provide cumulative safety data from five prospective clinical trials evaluating fecal microbiota, live-jslm (RBL) - the first microbiota-based live biotherapeutic product approved by the US Food and Drug Administration - for preventing rCDI in adults.

Design

Integrated safety analysis includes three phase II trials (PUNCH CD, PUNCH CD2, PUNCH Open-Label) and two phase III trials (PUNCH CD3, PUNCH CD3-OLS) of RBL.

Methods

Trial participants were at least 18 years of age with documented rCDI who completed standard-of-care antibiotic therapy before treatment with RBL. Assigned study treatment regimen was one or two doses of RBL (or placebo) administered rectally, depending on the trial design. In four of the five trials, participants with CDI recurrence within 8 weeks after RBL or placebo administration were eligible for treatment with open-label RBL. Treatment-emergent adverse events (TEAEs) were recorded for at least 6 months following last study treatment; in PUNCH CD2 and PUNCH Open-Label trials, TEAEs and serious TEAEs were collected through 12 and 24 months, respectively.

Results

Among the five trials, 978 participants received at least one dose of RBL (assigned treatment or after recurrence) and 83 participants received placebo only. TEAEs were reported in 60.2% of Placebo Only participants and 66.4% of RBL Only participants. Only abdominal pain, nausea, and flatulence were significantly higher in the RBL Only group compared with the Placebo Only group. Most TEAEs were mild or moderate in severity and were most frequently related to preexisting conditions. There were no reported infections for which the causative pathogen was traced to RBL. Potentially life-threatening TEAEs were infrequent (3.0% of participants).

Conclusion

Across five clinical trials, RBL was well tolerated in adults with rCDI. In aggregate, these data consistently demonstrated the safety of RBL.

Retrospective Analysis of the Safety and Efficacy of Fecal Microbiota, Live-jslm (REBYOTATM) Administered Under Enforcement Discretion to Patients With Clostridioides difficile Infection

Background

Fecal microbiota, live-jslm (RBL; REBYOTA™), the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration to prevent recurrent Clostridioides difficile infection (rCDI) in adults, has been evaluated in 5 prospective clinical trials. A retrospective analysis considered the safety and efficacy of RBL administered under US Food and Drug Administration enforcement discretion to patients with rCDI and broad eligibility criteria mimicking real-world practice.

Methods

We retrospectively identified adults with rCDI treated with RBL under enforcement discretion between November 1, 2015, and September 30, 2019, across 5 study sites. CDI diagnosis was based on site-specific practice. The primary safety set (PSS) included all patients who were naïve to previous RBL treatment and had continuously comprehensive medical records for 6 months following treatment.

Results

The primary treatment cohort had 94 patients; the PSS included 64 patients with common comorbidities receiving diverse chronic therapeutics. Most treatment-emergent adverse events were mild to moderate in severity and comparable between comorbidity subgroups and the overall population. There were no serious adverse events related to RBL or the administration procedure. In the PSS, 82.8% of RBL-treated patients responded at 8 weeks, of whom 88.7% had sustained response through 6 months. The number of RBL doses administered had no marked effect on outcome.

Conclusions

Together with prospective clinical trial outcomes, these findings support the efficacy and safety of RBL to prevent rCDI, with diagnostics and comorbidities representative of real-world clinical practice.

Microbiota-Based Live Biotherapeutic RBX2660 for the Reduction of Recurrent Clostridioides difficile Infection in Older Adults With Underlying Comorbidities

Background

Advanced age and underlying comorbidities are associated with greater rates of recurrence in patients with Clostridioides difficile infection (CDI). Reducing the likelihood of recurrence through treatment with an antimicrobial followed by a microbiota replacement therapy can decrease the burden of this infection and improve patient outcomes. We report the efficacy and safety of RBX2660, a microbiota-based live biotherapeutic, in older adults with recurrent CDI, grouped by comorbidities.

Methods

In this post hoc subgroup analysis of the PUNCH CD3 trial, we assessed outcomes in older adults (age ≥65 years) grouped by Charlson Comorbidity Index severity scores at screening (moderate [3-4] and severe [≥5]) and by the presence of underlying cardiac, renal, or gastrointestinal disorders.

Results

RBX2660 treatment success rates in older adults with comorbidities were consistent across subgroups and similar to those in the total RBX2660-treated population. A greater percentage of RBX2660-treated older adults remained free of CDI recurrence through 8 weeks following treatment compared with placebo-treated participants in all but 2 subgroups assessed. Across all subgroups, most treatment-emergent adverse events (TEAEs) were mild or moderate in severity and related to a preexisting condition. None of the serious or life-threatening TEAEs that occurred were related to RBX2660 or its administration. Occurrence of TEAEs did not cluster in any subgroup.

Conclusions

RBX2660 is efficacious and safe in older adults with recurrent CDI and underlying comorbidities.

522. Significant Improvement in Health-Related Quality of Life (HRQL) with RBX2660: Results from a Phase 3 Randomized, Placebo-Controlled Trial in Recurrent Clostridioides Difficile Infection (PUNCH CD3)

Background

Recurrence of Clostridioides difficile infection (rCDI) is common - up to 35% of patients may recur. RBX2660 is a microbiota restoration therapy to reduce rCDI. Here we report 8 weeks HRQL results using the Clostridioides difficile Health-related Quality-of-Life Questionnaire (Cdiff32), a disease-specific instrument, from PUNCH CD3 (a randomized, double-blinded, placebo-controlled RBX2660 Phase 3 trial, NCT03244644).

Methods

Cdiff32 includes three domains (physical, mental, and social) and a total score (all range from 0 to 100 [100 best possible]). Changes in Cdiff32 from baseline to week 8 were compared between RBX2660 and placebo (PBO) using unadjusted and adjusted analyses controlling for baseline score, demographic and disease characteristics. Per trial protocol, missing data were imputed via last observation carried forward (LOCF); as-observed data were also analyzed. Patients experiencing recurrence after blinded treatment received open-label RBX2660 per physician discretion; these participants were excluded unless, per LOCF, data were available from the blinded period for week 8 use.

Results

A total of 206 patients (140 RBX2660, 66 PBO) were included, with similar age (mean±SD) 61.1±16.9 yrs (RBX2660) and 57.3±16.4 yrs (PBO) and baseline Cdiff32 scores. More than half of the patients had multiple comorbidities. Cdiff32 scores improved significantly from baseline to weeks 1, 4, and 8 for both arms, with greater improvements for RBX2660 through week 8 (Figs. 1 & 2). At week 8, statistical differences were found for mental domain (unadjusted: 8.01±3.64; adjusted: 7.07, 95% confidence interval: [0.28, 13.86], both P< 0.05) and total score (adjusted: 6.11, [0.14, 12.08], P< 0.05), all favoring RBX2660. Results were similar for the as-observed analyses, with the adjusted physical domain also statistically favoring RBX2660.

Conclusion

Most patients in this study reported improved HRQL. Improvements were observed in both arms, but RBX2660-treated patients had more robust and sustained improvements with statistically significant differences in Cdiff32 scores. This study suggests that microbiome restoration therapy might positively affect HRQL; future research may link these improvements directly with microbiota changes.

Disclosures

Paul Feuerstadt, MD, FACG, AGAF, Ferring/Rebiotix Pharmaceuticals: Advisor/Consultant|Ferring/Rebiotix Pharmaceuticals: Grant/Research Support|Merck and Co: Advisor/Consultant|SERES Therapeutics: Advisor/Consultant|SERES Therapeutics: Grant/Research Support|Takeda Pharmaceuticals: Advisor/Consultant Erik R. Dubberke, MD, MSPH, Abbott: Advisor/Consultant|Ferring: Advisor/Consultant|Ferring: Grant/Research Support|Merck: Advisor/Consultant|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Seres: Advisor/Consultant|Summit: Advisor/Consultant|Synthetic Biologics: Grant/Research Support Amy Guo, PhD, Ferring Pharmaceuticals: Employee Adam Harvey, PhD, Ferring Pharmaceuticals: Employment Min Yang, MD, PhD, Analysis Group, Inc.: I am an employee of Analysis Group, Inc., which has received consulting fees from Ferring for the conduct of this study. Viviana García-Horton, PhD, Analysis Group, Inc.: Employee of Analysis Group, Inc., which received consulting fees from Ferring for the conduct of this study. Mirko Fillbrunn, PhD, Analysis Group, Inc.: I am an employee of Analysis Group, Inc., which has received consulting fees from Ferring for the conduct of this study. Glenn S. Tillotson, PhD, Ferring Pharmaceuticals: Advisor/Consultant|Paratek Pharmaceuticals: Grant/Research Support|Spero Pharmaceuticals: Advisor/Consultant|Taro Pharmaceuticals: Advisor/Consultant Lindy Bancke, PharmD, Rebiotix, a Ferring Company: Employee Kevin W. Garey, PharmD, MS, Acurx: Grant/Research Support|cidara: Advisor/Consultant|cidara: Grant/Research Support|Paratek: Grant/Research Support|Seres Health: Grant/Research Support|Summit: Grant/Research Support.

Efficacy and Safety of RBX2660 in PUNCH CD3, a Phase III, Randomized, Double-Blind, Placebo-Controlled Trial with a Bayesian Primary Analysis for the Prevention of Recurrent Clostridioides difficile Infection

BACKGROUND

Recurrent Clostridioides difficile infection, associated with dysbiosis of gut microbiota, has substantial disease burden in the USA. RBX2660 is a live biotherapeutic product consisting of a broad consortium of microbes prepared from human stool that is under investigation for the reduction of recurrent C. difficile infection.

METHODS

A randomized, double-blind, placebo-controlled, phase III study, with a Bayesian primary analysis integrating data from a previous phase IIb study, was conducted. Adults who had one or more C. difficile infection recurrences with a positive stool assay for C. difficile and who were previously treated with standard-of-care antibiotics were randomly assigned 2:1 to receive a subsequent blinded, single-dose enema of RBX2660 or placebo. The primary endpoint was treatment success, defined as the absence of C. difficile infection diarrhea within 8 weeks of study treatment.

RESULTS

Of the 320 patients screened, 289 were randomly assigned and 267 received blinded treatment (n = 180, RBX2660; n = 87, placebo). Original model estimates of treatment success were 70.4% versus 58.1% with RBX2660 and placebo, respectively. However, after aligning the data to improve the exchangeability and interpretability of the Bayesian analysis, the model-estimated treatment success rate was 70.6% with RBX2660 versus 57.5% with placebo, with an estimated treatment effect of 13.1% and a posterior probability of superiority of 0.991. More than 90% of the participants who achieved treatment success at 8 weeks had sustained response through 6 months in both the RBX2660 and the placebo groups. Overall, RBX2660 was well tolerated, with manageable adverse events. The incidence of treatment-emergent adverse events was higher in RBX2660 recipients compared with placebo and was mostly driven by a higher incidence of mild gastrointestinal events.

CONCLUSIONS

RBX2660 is a safe and effective treatment to reduce recurrent C. difficile infection following standard-of-care antibiotics with a sustained response through 6 months.

CLINICAL TRIAL REGISTRATION

NCT03244644; 9 August, 2017.

167. Efficacy of Investigational Microbiota-Based Live Biotherapeutic RBX2660 in Individuals with Recurrent Clostridioides difficile Infection: Data from Five Prospective Clinical Studies

Background

Microbiota-based treatments have shown promise to reduce recurrence, morbidity, and mortality for recurrent Clostridioides difficile infections (rCDI), but consistent and reliable clinical efficacy data are needed to support regulatory approvals that broaden patient access. Here we provide cumulative data from 5 prospective clinical studies evaluating RBX2660—a standardized, microbiota-based investigational live biotherapeutic—for reducing rCDI recurrence.

Methods

This analysis included three phase 2 (PUNCH CD, PUNCH CD2, PUNCH CD Open Label) and two phase 3 trials (PUNCH CD3, PUNCH CD3-OLS ad hoc analysis). All participants were ≥18 years old with documented rCDI who completed standard-of-care (SOC) oral antibiotic therapy prior to treatment with RBX2660. Depending on the trial, assigned study treatment was 1 or 2 doses of RBX2660 or placebo, with Treatment Success (TS) defined as remaining recurrence-free for 8 weeks after treatment. Treatment responders were monitored for additional recurrence through at least 6 months after receiving the last RBX2660 dose. Treatment non-responders were administered SOC antibiotic treatment and/or additional RBX2660 treatment and monitored for recurrence for 8 weeks after the last received RBX2660 treatment.

Results

Among the 5 trials with a total of 629 participants, RBX2660 consistently reduced the recurrence of rCDI, with TS rates ranging from 50 to 78.9% (Figure 1). Among primary non-responders, additional RBX2660 treatments further reduced recurrence and overall rates of TS ranged from 75.0% to 84.4% (Figure 2). Among CD, CD3, and CD3-OLS, a majority of primary responders remained CDI-free to 6 and up to 24 months with success rates ranging from 74.4% to 92.1%.

Conclusion

Among 5 trials with consistent investigational product and clinical endpoints, RBX2660 consistently reduced rCDI recurrence, with a majority of treatment responders remaining CDI-free for at least 6 and up to 24 months. Further, initial lack of response to RBX2660 did not preclude clinical benefit of additional RBX2660 treatment. Collectively, these data demonstrate consistency and reliability of the potential benefit of RBX2660 across an entire clinical program.

Disclosures

Lindy Bancke, PharmD, Rebiotix, a Ferring Company (Employee) Xin Su, MD, Rebiotix/Ferring (Employee)

LB5. A Long-Time Coming: Final 2-year Analysis of Efficacy, Durability, and Microbiome Changes in a Controlled Open-Label Trial of Investigational Microbiota-Based Drug RBX2660 for Recurrent Clostridioides difficile Infections

Background

Recurrent Clostridioides difficile infection (rCDI) is an urgent public health threat associated with significant mortality and medical cost. Microbiota therapy is gaining acceptance as a strategy to reduce rCDI recurrence. We present the final 24-month analysis of clinical safety, efficacy, and microbiome restoration from a Phase 2 open-label trial of RBX2660 for prevention of CDI recurrence.

Methods

Participants with multi-recurrent CDI received <2 doses of RBX2660 delivered via enema 7 days apart in this multicenter, open-label Phase 2 study. Efficacy was defined as the absence of CDI recurrence through 56 days after the last dose and was compared with 8-week recurrence-free rates for a historical control cohort that received standard-of-care antibiotic therapy. Fisher exact test compared the proportion of treatment participants who were CDI-free by age and sex. Durability was defined as continued absence of CDI episodes beyond 8 weeks. Safety and durability assessments occurred at 3, 6, 12, and 24 months. Participant stool samples were collected prior to and for up to 720 days after treatment, and microbiome changes were assessed by shallow shotgun sequencing.

Results

The efficacy of RBX2660 to prevent rCDI at 8 weeks (78.9%; 112/142) was higher than the CDI-free rate in the historical control group (30.7%, 23/75; P < 0.0001). Age and sex did not impact efficacy. Among participants who achieved treatment success at 8 weeks and were evaluable for long-term durability (n = 95), 8 experienced a new CDI episode by the 24-month follow-up for an overall durability of 91.6%. The safety profile was consistent with previous reports for RBX2660. In total, 503 stool samples from 110 treatment responders were analyzed. Within 7 days of treatment, the relative abundance of Bacteroidia and Clostridia remained shifted higher than pre-treatment levels while Gammaproteobacteria and Bacilli declined sharply after treatment, and these changes persisted to at least 24 months.

Conclusion

RBX2660, a microbiota-based drug, was safe and efficacious for preventing rCDI with clinical durability to 24 months after treatment, independent of age or sex, and RBX2660 durability associated with durable microbiome shifts from pre-treatment to a healthier composition.

Disclosures

Robert Orenstein, DO, Rebiotix Inc. (Advisor or Review Panel member), Sarah Mische, PhD, Rebiotix Inc. (Employee), Ken Blount, PhD, Rebiotix Inc. (Employee), Lindy Bancke, PharmD, Rebiotix Inc. (Employee), Xin Su, MD, MSci, Rebiotix Inc. (Employee), Dana Walsh, PhD, Rebiotix Inc. (Employee), Adam Harvey, PhD, Rebiotix Inc. (Employee), Carlos Gonzalez, MS, Rebiotix Inc. (Consultant), Dale N. Gerding, MD, Rebiotix Inc. (Board Member).